The Senate approved a resolution Wednesday that aims to undo a sweeping act of deregulation undertaken last year by the Federal Communications Commission, issuing a rebuke to the Trump administration, which supported the FCC's move.

The resolution targets the FCC's vote in December to repeal its net neutrality rules for Internet providers. If successful, the legislative gambit could restore the agency's regulations and hand a victory to tech companies, activists and consumer advocacy groups.

The congressional effort comes less than a month before the rules are officially expected to expire, on June 11. And the high-profile vote could shine a spotlight on lawmakers running for reelection during a tough midterm season.

“The Senate vote, on the eve of midterms, could have significant political effects,” said Marc Martin, a telecom lawyer at Perkins Coie in Washington. But, he cautioned, it remains unclear how many voters will actually be motivated by net neutrality to go to the polls.

Senate supporters of the FCC rules put forward the legislation under the Congressional Review Act, a law that permits Congress to revisit — and reject — decisions by administrative agencies within a certain window of their approval. The resolution, or CRA for short, passed with the backing of all 49 Democratic senators and three Republicans: Sens. Susan Collins of Maine, John N. Kennedy of Louisiana and Lisa A. Murkowski of Alaska.

Sen. Edward J. Markey (D-Mass.), who led the CRA effort, called the vote a victory for democracy and the economy on Wednesday afternoon.

“When we talk about a free and open Internet, we mean it is free from corporate control,” said Markey, who called on the House to take up the measure.

Kennedy, whose vote was closely watched, as he was one of the few Republicans siding with Democrats on the issue, said he was ultimately persuaded to vote yes because more than 1 in 5 Louisianans lack choice in their broadband provider.

“It was a fairly close call, but I'll tell you what it comes down to: the extent to which you trust your cable company,” Kennedy told The Washington Post moments after casting his vote. “If you trust your cable company, you're not going to like my vote today. If you don't trust your cable company, you will.”

Kennedy's vote was highly sought by Democrats in the run-up to the vote. Markey and Kennedy have met and discussed the issue numerous times in recent weeks, according to a Democratic aide, and the two lawmakers' staffs have been in “constant communication.”

However, Sen. John Thune (R-S.D.), the chairman of the Senate committee that oversees the FCC, called the vote a political stunt and repeatedly said Wednesday it would lead nowhere. "Despite this vote, I remain committed to finding a path to bipartisan protections for the Internet and stand ready to work with my colleagues on the other side of the aisle when they are ready as well,” he said.

Still, it is unclear what fate may await the measure in the House. Senate Minority Leader Charles E. Schumer (D-N.Y.) urged the House to take up the issue quickly.

“House Republicans don't have to choose the same path that the vast majority of Republicans in the Senate chose,” Schumer said at a news conference Wednesday afternoon. “The American people have spoken. Speaker Ryan should listen.”

House Majority Leader Kevin McCarthy (R-Calif.) has said lawmakers in that chamber are focused on designing their own legislation to “permanently address this issue,” casting doubt on whether the Senate resolution can advance. And, given the White House's endorsement of the FCC's repeal, analysts say, it is unlikely that Trump will sign the resolution to make it effective. (In one of his first acts of office, Trump last year signed a Republican-backed CRA overturning other FCC rules that established new privacy protections for Internet users.)

The net neutrality regulations, imposed on broadband companies such as AT&T, Verizon and Comcast in 2015, banned the industry from blocking or slowing down websites. The rules also prohibited those companies from offering websites and app developers faster, easier access to Internet users in exchange for extra fees — a tactic that critics described as digital “fast lanes” that could distort online competition in favor of large, wealthy businesses.

Despite surviving a court challenge from broadband industry groups seeking to overturn the rules in 2016, they came under fire again a year later — this time from the agency's new Republican leadership. FCC Chairman Ajit Pai led the charge against the net neutrality regulations, calling them an example of government overreach that discouraged Internet providers from investing in upgrades to their networks.

Pai said his agency's “light-touch” approach would lead to better, faster Internet service for Americans — and more competition.

Last November, a month before he and the FCC's two other Republicans, Michael O'Rielly and Brendan Carr, voted to repeal the rules, Pai said, “Under my proposal, the federal government will stop micromanaging the Internet.”

The agency's two Democrats at the time, Mignon Clyburn and Jessica Rosenworcel, voted to keep the rules on the books.

On Wednesday, Pai said: “It’s disappointing that Senate Democrats forced this resolution through by a narrow margin. But, ultimately, I'm confident that their effort to reinstate heavy-handed government regulation of the Internet will fail.”

Pai's opponents have said the rules are a necessary consumer protection as the Internet has become more vital to supporting the economic livelihoods of everyday Americans. In surveys, solid majorities say they support the principle of net neutrality, generally, and the FCC's rules, in particular.

“Pai's so-called 'Restore Internet Freedom' order was built on a mountain of false premises — about the law, the state of investment ... and public sentiment,” Tim Karr, a consumer advocate at Free Press, tweeted Tuesday.

In response to Wednesday's vote, AT&T said it was committed to a lasting legislative compromise between Republicans and Democrats on the issue.

“We reiterate our call for actual bipartisan legislation that applies to all internet companies and guarantees neutrality, transparency, openness, non-discrimination and privacy protections for all internet users,” the telecom giant said in a statement.

On Wednesday, start-up advocacy group Engine praised the vote: "Fortunately, a majority of Senators ... voted today to preserve internet openness. Congress has an opportunity to do the right thing for the start-ups who depends on the internet, and we hope the House will also approve the CRA soon.”

Trade groups representing Internet providers sent a letter to Capitol Hill on Tuesday urging lawmakers to vote against the CRA. Calling on Congress to reject the resolution in favor of developing bipartisan legislation to replace the FCC rules, the groups argued that the CRA does “nothing” to address the data mining and other practices of tech companies who have come under growing scrutiny for their role in facilitating the spread of online misinformation and harassment.

The Internet Association, a trade group backed by Facebook, Uber and others, has said that regulations targeting Silicon Valley on hate speech risks running afoul of the First Amendment. It also said last week that consumers demand strong and enforceable net neutrality rules on Internet providers.

“It is essential that rules be reinstated through any means necessary, including the CRA, courts, or bipartisan legislation,” the group said in a statement.

Tony Romm contributed to this report.

Brian Fung covers business and technology for The Washington Post. Before joining The Post, he was the technology correspondent for National Journal and an associate editor at the Atlantic.